Such communications equipment has been standardized by the German Federal Postal Administration, for example, under the designation "Bauweise 7R". As is disclosed in published German patent application No. 35 27 914, at the supports or uprights of a rack which is designed to receive subracks, devices for receiving such subracks are fixed one above the other at the necessary intervals. The devices for receiving subracks have guide bars for inserting subracks and are provided with connectors which cooperate with complementary connectors of the inserted subracks.
The connectors of each subrack-receiving device are floatingly mounted in a conventional manner in holes of a mounting plate which is formed, for example, by a U-shaped sheet-metal bar and which in turn is screwed up, for example, a cable support of the subrack-receiving device. The male and female halves of such connectors are designed, for example, to provide connections for coaxial cables or, increasingly, optical waveguides.
A special aspect of the 7R equipment practice is that the height of the subracks is usually equal to a multiple of their width or depth and that therefore the danger of tilt is increased when they are inserted into the subrack-receiving devices. Axially parallel deviations of the connectors in relation to each other are compensated for by mounting them in a floating manner. Compensation is not possible, however, if, as a result of a tilting motion by the subrack about the lower front edge, the connector is brought into a tilted position in which its axis deviates from the insertion axis; it can thus cause misalignment. However, in optical waveguide connectors, attenuation in the connection increases dramatically if the insertion axes of the connectors to be joined are not in precise alignment.